In the recent past self-propelled agricultural harvesting machines are known that are equipped with constantly stronger internal combustion engines that, at the present time, can deliver more that 800 KW. Due to the relative low production quantity in which such high powered engines are produced, these engines are relatively more costly in each case than two internal combustion engines with half the power output. Moreover, the entire output of the engine is not always required—therefore it is not necessary for example for transportation on public roads or for the harvest of grass—which leads to a lower efficiency of the engine compared to full power operation, it has therefore been proposed (EP 1 640 201 A1) that a harvesting machine be equipped with two internal combustion engines, of which, in addition to the first internal combustion engine, one can be started to meet greater power requirements.
According to EP 1 640 201 A1 the crankshafts of the two internal combustion engines are arranged horizontally and transverse to the forward operating direction, where one internal combustion engine is arranged ahead of the other internal combustion engine in the direction of operation. A spur gear drive establishes a connection between the crankshafts of both internal combustion engines and the main drive-line of the harvesting machine. Between one of the two internal combustion engines and the spur gear gearbox a clutch, that can be disengaged, is arranged in order to be able to drive the harvesting machine with only a single internal combustion engine, without having to let the other internal combustion engine run along with it. Both internal combustion engines are mounted, together with the spur gear gearbox on an auxiliary frame, so that they form a compact arrangement for a group of components that can be preassembled.
Another forage harvester is described by EP 1 813 459 A1. The internal combustion engines are arranged transverse to the forward operating direction and one behind the other. A belt drive gearbox connects the crankshaft of the rear internal combustion engine with the crankshaft of the forward internal combustion engine that in turn drives a drive belt that is connected so as to drive the largest power consumers (chopper drum and blower).
DE 10 2007 019 661 A1 that is seen as forming a class, described an agricultural forage harvester with two internal combustion engines arranged side by side alongside each other, that extend in the direction of operation, whose crankshafts are connected to an angle drive gearbox by articulated shafts and a spur gear gearbox, which drives a drives a belt pulley over a transverse shaft which in turn drives a chopper drum over a main drive belt.
DE 37 22 367 A described an agricultural forage harvester with a single internal combustion engine arranged above the rear axle, whose crankshaft extends to the front in the direction of operation and is connected by an articulated shaft to a bevel gear distribution gearbox, that drives an output shaft extending transverse to the forward operating direction, which in turn brings a chopper drum into rotation over a belt drive. Moreover, the bevel gear distribution gearbox mechanically drives the front wheels of the forage harvester; the drive for the front harvesting attachment and the pre-pressing rolls is derived from the input shaft connected to the articulated shaft of the bevel gear distribution gearbox.
In drive arrangements with internal combustion engines arranged in the transverse direction, as they are described in EP 1 640 201 A and EP 1 813 459 A, it can be seen as detrimental that the possible maximum width of the harvesting machine permits only a limited length of the engines and thereby also limits the maximum possible power output. This disadvantage is avoided with engines arranged in the longitudinal direction (DE 10 2007 019 661 A), in which however the output shaft of the spur gear gearbox that combines the power output of the internal combustion engines is arranged in the longitudinal direction, which is shown to be a disadvantage since a further angular gearbox is required, in order to drive a sideways belt drive for the largest power consumers, which increases the construction cost and the number of gear meshes in the driveline and negatively affect the efficiency.